The purpose of the proposed project is to develop an in vitro system for long-term electrophysiological studies on the isolated brain of the giant garden slug, Limax maximus. A search will be made for spontaneously active neurons with distinctive firing patterns whose activity can be recorded through suction electrodes applied to particular roots and connectives of a freshly isolated brain. In addition, an attempt will be made to identify and characterize stereotyped reflex responses in which efferent neural activity can be modified by electrical stimulation of nerve trunks. Once reliably identifiable units or reflexes are determined, these will be used to assess the ability of trial culture media to preserve normal neural function in isolated slug brains for up to one week. A perfusion system and mechanism for precise temperature control of the electrical recording chamber will also be developed.